Patent CZ-305251-B6 (CZ)
Title: Method of determining front-rear and side incline of a vessel or aircraft with exclusion of dynamic errors and measuring modular system for carrying out the method
Inventor: DICHEV DIMITAR ANDONOV
IPC: G05D1/08
Filed: 2013-12-10
Abstract: The method of determining front-rear and side incline of a vessel or aircraft, according to the present invention, is characterized in that actual values of t he side incline of a vessel or an aircraft are measured and registered according to angular swing of a local vertical axis (12) of a physical pendulum (1) by means of a first photoelectric code converter (2) mounted on the corresponding axis for measuring angles of side incline as well as front-rear incline of a vessel or an aircraft by means of a second photoelectric code converter (3) mounted on the corresponding axis for measuring angles of the front-rear incline. Dynamic error caused by instability of the physical pendulum (1) within inertial space expressed by a deviation from the local vertical axis (12) is determined and removed through the mediation of two pairs of structurally identical accelerometers (4, 5, 6, 7) intended for measuring linear acceleration resulting from the front-rear incline of a vessel or aircraft and side incline of a vessel or aircraft. Through processing signals from the accelerometers (4, 5, 6, 7) through the mediation of a selected frequency of scanning the linear acceleration of the front-rear and side incline of a vessel or aircraft, an actual value of a dynamic error is obtained wherein the dynamic error is then removed from the signals of both the first photoelectric code converter (2) and the second photoelectric code converter (3) by doubled integration of the observed values. Further cleaning of signals from both the photoelectric code converters (2, 3) from interference effects is carried out by linearization of both the observed accelerations through both a first Kalman filter (10) and the second Kalman filter (11), to thereby obtaining output signals that are proportional to the deviations of the physical pendulum (1) from the local vertical axis (12) in both degrees of freedom, i.e. the front-rear and side incline of a vessel or aircraft. A modular measuring system (9) for determining front-rear and side incline of a vessel or aircraft comprises a body (8), which id fixedly attached to a vessel or an aircraft. The modular measuring system (9) further comprises a physical pendulum (1) swinging in two degrees of freedom of directions perpendicular to each other and determined by the front-rear and side incline of a vessel or aircraft and a physical pendulum (1), representing a local vertical axis (12), which is mechanically coupled with both a first photoelectric code converter (2) arranged on the main axis for measuring angles of side incline of a vessel or an aircraft and a second photoelectric code converter (3) arranged on the main axis for measuring the front-rear incline of a vessel or aircraft. A first accelerometer (4) is arranged on the body (8) of the modular measuring system (9), while a second accelerometer (5) is arranged on the first photoelectric code converter (2). A third accelerometer (6) is also arranged on the first photoelectric code converter (2). A fourth accelerometer (7) is arranged on physical pendulum (1). The output signals of the first accelerometer (4) are supplied along with the output signals of the first photoelectric code converter (2) to the output of the second accelerometer (5) and subsequently to the first Kalman filter (10). The output signals of the third accelerometer (6) are supplied to the output of the fourth accelerometer (7) and subsequent they are supplied along with the output signals of the second photoelectric code {alpha} converter (3) to the second Kalman filter (11).